Preparation of phytosterol glucosides



Patented Dec. 29, 1942 PREPARATION OF PHYTOSTEROL GLUCOSIDES David P. Langlois, Decatur, 111., assignor to A; E. Staley Manufacturing Company, Decatur, 111., a corporation of Delaware No Drawing. Application July '19; 1940,

Serial No. 346,407 1 I 14 Claims.

The present invention relates to the recovery of glucosides and relates in particular to the production of glucosides of the phytosterol type from naturalnvegetable oils.

7 Glucosides of this type are practically universal constituents of natural vegetable oils, but considerable difliculty has been encountered in their recovery from the oil. It has been suggested to recover the phytosterol glucosides from oil-bearing substances by contacting the oil with an adsorbent such .as activated alumina. This and the other known methods of recovery have not been satisfactory and a principal object of the present invention is the provision of a method by which phytosterol glucosides may be recovered easily and economically from oil-bearing substances.

A further object of the invention is the provision of a phytosterol glucoside recovery process which includes the treatment of a natural vegetable oil with a Water solution of an alkali such as sodium hydroxide, the amount of the alkaline solution being around 3 or 4 times greater than that required to neutralize the .free .fatty acid content of the oil, centrifuging the alkali-treated oil to separate a soap-containing fraction,. and acidulating this fraction to provide a. threephasemixture from which the .glucoside may be isolated.

A still further object of. .the invention is the separation or recovery of phytosterol glucosides from refinery foots obtained from a raw vegetable oil.

Various types of vegetable oilsare used extensively in the. production .of edible fats, soap and the like. Generally these oils are produced by pressing the seed .from which they are obtained, this pressing operation being efiective to liberate a crude .011 containing substances other than triglycerides. Among the other substances present in the crude oil are phosphatides, glucosides, and certain unsaponifiable substances, each of these classes of materials .beingpresent in relativelyvsmall quantities which makes their recovery or separation from the triglycerides-generally diflicult.

Theglucosides in general have been isolated or recovered from the oil only in quantities sufficient for identification or laboratory experimentation. Phytosterols are of considerable valuein the synthesis of various important biological compounds, but their use inthis connection has been inhibited by the lack of asuitable supply offthematerial,

In accordance with the parl amenta ian. 6c

cosides from which phytosterol may be produced are recovered from oil-bearing substances in substantial quantities and at a relatively low cost.

' The process involves the treatment of a raw vegetable oil with, a small quantity of an aqueous solution of sodium'hydroxide. While the amount of the alkali solution and its concentration'may vary to a considerable extent, it is preferred to employ a quantity of the solution somewhat in excess 01 that necessary to neutralize the free fatty acid content of the raw oil. In carrying out this alkali treatment the alkali solution may be added to the oil at a temperature of around F. and themixture maybe agitated for a period of time suflicient to effect neutralization of the free fatty acid content of the oil and to expend the alkali. I

Followingthel alkali treatment the oil is passed through a centrifuge of any suitable type, and as a result of the centrifuging there is separated a soapy, water and oil mixture of a volume which may represent a loss of approximately 4 per cent of the oil. I I

This soapy'fraction contains the soap resulting from the neutralization of the free fatty acid content of the il by the alkali and the soap which mayhave been produced by the slight excess of alkali in saponifying neutral oil. Additionally, there will be present a small quantity of neutral oil.

The soapy fraction further will be found to contain a high concentration of phytosterol glucosides as well as some phosphatides, glycerine and water. It is possible to make an efiective separation of the phytosterol glucosides from the soapy fraction. This separation is based upon the acidulation of the soapy fraction. In carrying out this acidulation a sufficient quantity ofan acid such as sulfuric acid may be added to the mixture to provide a pH of between about 2 and 5. Steam may be passed through the acidulated mixture for a short time until there is observed a break in the emulsion. Upon standing, the acidulated mixture separates into three layers. The top layer consists primarily of free fatty acids and the bottom layer'is composed principally of water, glycerine and dissolved salts. The center layer consists of an emulsion containing a high concentration of the phytosterol glucoside. The'top and bottom layers maybe siphoned off, and the phytosterol'glucosides then may be recovered from the middle layer by the addition of a sufiicient quantity of alcohol to break the'emulsion into two phases. The quantity of alcoholrequired for this operation may be ing step comes within the class of degummingl foots normally produced in the refining of raw vegetable oils. I have found that this class of I materials is a rich source of phytosterol glucosides steam then was turned off and the mixture was allowed to stand while cooling. After 16 hours the mixture had separated into three distinct layers. The top oily layer was siphoned off and the bottom water layer also was siphoned off, the

middle layer being allowed to. remain in the tank.

which makes their commercial recovery feasible.

Vegetable oil foots may be produced simply by allowing the oil to stand for the time necessary for the separation of tank settlings. Water wash-- ing of oil also results in the separation of foots from the oil. Generally, though, the foots'ar'e produced by an alkali refining process of the type described above, and separation of the foots produced by the alkali treatment may be by settling or centrifuging. The strength of the alkali solution may vary widely, as is well known in oil refining practice. Carbonates, silicates, phosphates and other alkaline materials may be employed in the alkali refining process for the separation of the foots from the oil. The oilinsoluble foots contain relatively large amounts of phytosterol glucoside, regardless of the particular method employed for inducing the separation of the foots from the oil. Generally the foots will contain residual quantities of neutral oil which are separated from the main body of the oilwith the removal of the foots. Regardless of the particular treatment of the oil incident to separation of the foots, the treatment of the fonts for recovery of phytosterol glucosides will follow substantially the procedure given herein.

In a preferred embodiment of the invention the foots are subjected to a further treatment with an additional quantity of alkali to completely saponify the residual neutral oil contained in it. After the substantially complete saponification of the oil the foots are treated with an acid in the manner described before to provide a pH of from 2 to 5 and the recovery of phytosterol glucosides is affected as referred to'above. This further alkali treatment is effective to hydrolyze practically all of the phosphatides present in the foots and this elimination of the phosphatides is of value in the subsequent effective separation of phytosterol glucosides.

As an example of the operation of the process 3,000 pounds of soybean oil were fairly mixed with 135 pounds of 14 Baum (9.5 per cent) caustic soda solution. The mixture was agitated in mixing tanks to insure complete neutralization To this remaining middle layer was added gallons of alcohol, the mixture being thoroughly stirred during the addition of the alcohol. As a result of the addition of the alcohol, the mixture s'eparated into a solid phase and a liquid phase. The liquid was removed by filtration and the remaining solid phase was washed with about 5 gallons of alcohol. After drying the resulting solids it was found thatthe solids weighed 9 pound of which 4.5 pounds were crude glucoside and 4.5 pounds were water-soluble salts. By washing with water and centrifuging there was recovered of all'of the free fatty acids. It then was 'run to a centrifuge where'the soapy residue was separated from the oil. The amount of the soapy fraction recovered was 240 pounds.

This residue then was run into a tank and diluted with a small amount of water equal to about 50 pounds. Then 58 pounds of 40 Baum caustic soda solution was added and the mixture was brought to the boiling point by steam injection. After 2 hours boiling no further change was noted in the free alkali of the mixture and insoluble materials and. then allowed to cool;

On cooling, the phytosterol is filtered ofl.

As before stated, glucosides may be recovered from the various vegetable oils in the manner decrystallizes out and scribed herein. Drying oils such as linseed oil,

semi-drying oils such as soybean oil, and nondrying oils such as corn oil are other examples of oils which may be treated. Cottonseed oil and the like also may be treated in accordance with the process. Soybean oil is a preferred material from which to recover the glucosides.

It will be recognized that many changes in and additions to the process described herein for purposes of explanation may be made Without de- 3 parting from the scope of 'the invention as defined in the appended claims.

I claim:

1. The process of producing phytosterol glucosides, which comprises subjecting a vegetable oil to a neutralizing treatment to neutralize-the free fatty acid content of the oil, separating the resulting soapy fraction from the oil, acidulating the soapy fraction and heating the same, allowing the acidulated fraction to stand to produce an upper fatty acid layer, a bottom layer, and

a middle layer containing phytosterol glucosides and precipitating phytosterol glucosides from the resulting middle layer.

2. The process of producing phytosterol glucosides, which comprises subjecting a vegetable oil to a neutralizing treatment to neutralize the free fatty acid content oftheoil, separatingthe resulting soapy fraction from the oil by centrifugal action, acidulatiug the soapy fraction and applying heat thereto, allowing said fraction to stand .to-provide a three-phase mixture having an upper fatty acid layer, a lower water layer, andla middle layer containing phytosterol gluocidesjand precipitating. phytosterol glucosides from said middlelayer. 5

3. The methodof recovering phytosterol glucosides, which comprises subjecting a' ra wyegetable oil containing said glucosides .to .a neutralizing treatmentv to neutralize the nee-racy acid content of said 011 and to saponify "a small quantity of neutral oil, subjecting the oil to centrifuging to produce a soapy fraction containing neutral oil, soap, phosphatides, glucosides and water, subjecting the soapy fraction to a further neutralization treatment, acidulating the soapy fraction to a pH of between 2' and 5 and heating the same, allowing the fraction to stand to produce a liquid mixture capable of separating into an upper fatty acid layer, a bottom water layer, and a middle glucoside-containing layer upon standing, and precipitating phytosterol glucosides from the middle layer.

4. The process of recovering phytosterol glucosides from vegetable oils containing the same, which comprises subjecting the oil to treatment with a relatively dilute alkaline solution in a quantity sufficient to neutralize the free fatty acid content of the oil and to saponify a small quantity of the oil, subjecting the oil to centrifugal action to remove a soapy fraction containing soap, neutral oil, phosphatides, phytosterol glucosides, and. water, subjecting the soapy fraction to further treatment with an alkali to hydrolize said oil and said phosphatides, acidulating the soapy fraction to a pH of between 2 and 5, allowing the acidulated fraction to stand to produce an upper fatty acid layer, a bottom water layer, and a middle layer containing phytosterol glucosides and inorganic salts, recovering said middle layer, treating said middle layer with alcohol to precipitate said glucosides and inorganic salts, and washing the precipitate to remove said salts.

5. The method of producing glucosides, which comprises acidulating vegetable oil refinery foots and applying heat thereto, allowing said acidulated foots to stand to produce an upper fatty acid layer, a bottom aqueous layer, and an intermediate layer, separating said intermediate layer, and treating said intermediate layer to precipitate phytosterol glucosides.

6. The method of producing glucosides, which comprises acidulating soybean oil refinery foots to a pH of between 2 and 5 and heating the same, allowing the acidulated foots to stand to produce an upper fatty acid layer, a bottom water layer, and an intermediate layer, and adding a sufficient quantity of alcohol to said intermediate layer to precipitate phytosterol glucosides.

'7. The method of producing glucosides, which comprises subjecting vegetable oil degumming foots to a neutralization treatment, acidulating the foots and heating the same, allowing said acidulated foots to stand to produce an upper fatty acid layer, a bottom water layer, and an intermediate layer containing phytosterol glucoside, and precipitating said glucoside from said intermediate layer.

8. The method of producing glucosides, which comprises subjecting vegetable oil degumming foots to a neutralization treatment, acidulating the foots to a pH of between 2 and 5 and heating the same, allowing the acidulated foots to stand to produce an upper fatty acid layer and a lower layer containing said glucosides, separating said lower layer, and treating said lower layer with alcohol to precipitate phytosterol glucoside.

9. In the process of producing phytosterol glucosides wherein a. vegetable oil is subjected to a neutralization treatment to neutralize the free fatty acid content of the oil and a resulting soapy fraction is acidified, the improvement which comprises allowing the fraction to stand to provide a three-phase mixture having an upper fatty acid layer, a lower water layer, and a middle layer containing phytosterol glucosides, and precipitating phytosterol glucosides from said middle layer.

10.. In the process of treating oils containing phytosterol glucosides wherein the oil is treated with an alkaline solution in a quantity sufficient to neutralize the free fatty content of the oil to saponify a portion thereof, and thereafter separating and acidulating th'e soapy fraction, the improvement which comprises allowing the acidulated fraction to stand to produce an upper fatty acid layer, a bottom water layer, and a middle layer containing phytosterol glucosides and inorganic salts, recovering said middle layer and treating the same with alcohol to precipitate said glucosides and inorganic salts and thereafter washing the precipitates to remove said salts.

11. In the method of producing glucosides in which vegetable oil refinery foots are acidulated, the improvement which comprises allowing said acidulated foots to stand to produce an upper fatty acid layer, a bottom aqueous layer and an intermediate layer, and thereafter separating said intermediate layer and. precipitating the same to recover phytosterol glucosides.

12. In the method of producing glucosides in which soybean oil refinery foots have been acidulated to a pH of between 2 and 5 and thereafter heated, the improvement which comprises allowing the "acidulated foots to stand to produce an upper fatty acid layer, a bottom layer, and an intermediate layer, and thereafter adding a sufficient quantity of alcohol to said intermediate layer to precipitate phytosterol glucosides.

13. In the method of producing glucosides wherein vegetable oil degumming foots have been subjected to a neutralization treatment and acidulated, the improvement which comprises allowing said acidulated foots to stand to produce an upper fatty acid layer, a bottom water layer, and

an intermediate layer containing phytosterol glucoside, and thereafter precipitating said glucoside from said intermediate layer.

14. In the method of producing glucosides in which vegetable oil degumming foots have been subjected to a saponification treatment with an alkali and the foots thereafter acidulated to a pH of between 2- and 5, the improvement which comprises allowing said acidulated foots to stand to produce an upper fatty acid layer and'a lower layer containing said glucosides, and thereafter separating said lower layer and precipitating the same with alcohol to precipitate phytosterol glucoside.

DAVID P. LANGLOIS. 

